Question
Calculate mean deviation about median age distribution of $100$ persons given below:
Age
$16-20$
$21-25$
$26-30$
$31-35$
$36-40$
$41-45$
$46-50$
$51-55$
No. of persons
$5$
$6$
$12$
$14$
$26$
$12$
$16$
$9$

Answer

Converting the given data into continuous frequency distribution by subtrading $0.5$ from the lower limit and adding $0.5$ to the upper limit of each class interval.
Age
$x_i$
$f_i$
Comulativefrequency
$|d_i| = |x_i - 38|$
$f_i|d_i|$
$15.5-20.5$ $18$ $5$ $5$ $20$ $100$
$20.5-25.5$ $23$ $6$ $11$ $15$ $90$
$25.5-30.5$ $28$ $12$ $23$ $10$ $120$
$30.5-35.5$ $33$ $14$ $37$ $5$ $70$
$35.5-40.5$ $38$ $26$ $63$ $0$ $0$
$40.5-45.5$ $43$ $12$ $75$ $5$ $60$
$45.5-50.5$ $48$ $16$ $91$ $10$ $160$
$50.5-55.5$ $53$ $9$ $100$ $15$ $135$
 
 
$\text{N}=\sum\text{f}_\text{i}=100$
 
 
$\sum\text{f}_\text{i}|\text{d}_\text{i}|=735$
clearly, $N = 100$
$\Rightarrow\frac{\text{N}}{2}=50.$
Cumulative frequency is just greater than
$\frac{\text{N}}{2}$ is $63$ and the corresponding class is $35.5 - 40.5.$
$l = 35.5, f = 26, h = 5, F = 37$
Therefore, $\text{Median}=\text{l}+\frac{\frac{\text{N}}{2}-\text{F}}{\text{f}}\times\text{h}=35.5+\frac{50-37}{26}\times5=38$
$\text{M.D}=\frac{1}{\text{N}}\sum\text{f}_\text{i}|\text{d}_\text{i}|=\frac{735}{100}=7.35$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free